Colour printing help?

pentaxuser · Sep 17, 2007

pentaxuser said:
PE Thanks. If I have understood your correctly the plus for CD4 is its ability to develop at lower temp than the standard 45 sec at 35 degrees centrigrade. The big minus is its worse dyes and lower stability.

Yet the Kodak RA-RT kit is OK at room temp. So what does the Kodak kit contain which makes it OK at room temp. Is this the CD3 that Nick Zentenna mentions?

Will a CD4 kit operate at 35 dgrees C in addition to lower temps and if it does, do the same problems of worse dyes and lower stability manifest themselves? If anyone were to use a CD4 kit at 35 degrees C would the quality problems be there from the start or only appear in a matter of months, years etc. What timescale for such problems did your research indicate?

As the original OP indicated such info isn't easy to find out. Last night I checked for any reference to CD4 and found it on one label but this was for C-41 developer. Based on Nick's post it looks as if CD4 for C-41 is in fact the correct stuff so I need have no worries there.

Most of us have to trust that the suppliers are producing the correct kit. The chemistry of colour processing for both C-41 and RA4 is knowledge that's way beyond my reach.

Someone, Nick I think, said that Kodak or Fuji kits will be fine, Unfortunately Fuji-Hunt kits as it they are called in the UK seem to be even harder to find than Kodak's.

On Kit information and because we are the other side of the Atlantic, any contribution from UK users would be most welcome as well.

Thanks

pentaxuser

PE. This thread seems to have died a natural death. I appreciate that threads have lives and deaths of their own and take different twists and turns which can sometimes mean that some questions remain unanswered inadvertently.Is there any chance that you may be able to give answers to my questions? I hope that more than just me will benefit.

Thanks

pentaxuser

Photo Engineer · Sep 17, 2007

Sorry, I missed those posts.

CD4 was used to speed up development many years ago. Some manufacturers still use it to speed up processing and charge a premium price for the kit. The use of CD4 was touted years ago by Pat Dignan. I corresponded with him shortly before his death, and was discussing the image stability question with him at that time. He was considering abandoning the use of CD4 based on his subsequent tests of image stability.

Kodak paper now develops more rapidly and therefore CD4 gives no boost, but speedup kits are still sold at a premium price. IMHO, they are not needed due to the paper improvements. The RA-RT developer works just fine for me from 68 - 100 deg F (20 - 38.5 C).

PE

pentaxuser · Sep 17, 2007

PE. Wow that was quick. If we'd been in phone contact, it wouldn't have been much faster.

It's clear that Kodak papers because they are faster now work fine at RT without having to risk the dangers of CD4 developer. I would assume that Fuji papers in Kodak RT developer would work equally well although the proof of this needs to be from someone who uses Fuji paper in Kodak developer and better still someone else who uses RT developer other than Kodak at room temp. I think Tetenal give temps down to RT for their developer but maybe a Tetenal user will contribute.

Many thanks once again for the quick response

pentaxuser

Photo Engineer · Sep 17, 2007

I have no recent experience with Fuji papers or developers. Sorry.

Kodak paper develops fully in 2 minutes at 68 deg F and in 1 minute or less at 100F. I use 45" to 1' myself.

Tetenal rapid developers with CD4 or any other change only does so at the cost of a premium price with no other benefit in my opinion.

Kodak achieved the RA process by a redesign of the emulsions to speed development rate and bring it more in line with B&W papers. It used to be that the cyan developed first, then magenta and then yellow due to diffusion effects and grain size and type. Most of that has been solved with the new, high chloride emulsions.

BTW, these emulsions appear to go to completion and do not easily go into fog or change color balance very much with errors in processing. There is a slight shift in color balance from 100 -> 68 deg F in the direction of yellow, in my experience, so you may need some additional yellow, about 10Y.

PE

ben-s · Sep 17, 2007

Interesting stuff. Thanks All.

I'm afraid I've let the thread go silent, but with moderately good reason - I rented the rather excellent Canon 24-70 f/2.8 L over the weekend, and I've been burning film and silicon (naughty, naughty) with it
When I get paid, I think I will have a go at colour printing.

PE (or anyone else), please could you tell me exactly which Kodak individual chemicals I will need? - I can't make head or tail of the cryptic product names without descriptions on Calumet's site. Thanks

Photo Engineer · Sep 17, 2007

I have posted the Kodak developer number several times here. It is the RA-RT developer. I would not mix it from scratch.

The developer comes in 5 and 10 L kits and I buy the 10 L kits which I divide up into 2 portions. I make 2 kits.

Use the RA Blix and a 2% stop.

PE

ben-s · Sep 18, 2007

Thanks PE. - I wasn't planning to mix from raw chemicals, by single chamicals, I meant the concentrates for a single solution, rather than the complete RA4 kit. My post wasn't overly clear.

I've managed to find the kit on the Calumet US site, but it's not listed in the UK. I'm looking at other suppliers now...

ben-s · Sep 18, 2007

OK, Firstcall seem to have the appropriate stuff;
Kodak Ektacolor Pro RA4 Starter, 1 litre
Kodak Ektacolor Pro RA4 Developer, 2 x 5 litres
Kodak Ektacolor Pro RA4 Bleach Fix, 4 x 5 litre

It seems extremely difficult to find kodak chemicals in the UK. I've looked at about 15 suppliers, and many of them don't even list kodak stuff at all. If they do list it, it's badly described.

Nick Zentena · Sep 18, 2007

ben-s said:
OK, Firstcall seem to have the appropriate stuff;
Kodak Ektacolor Pro RA4 Starter, 1 litre
.

I don't remember the Kodak line but starter is normally mixed with developer to make a seasoned tank. It's not what you buy on it's own. I'm fairly sure Kodak makes/made a developer that didn't need a starter. Thats the one you want.

Or you could buy the starter and a jug of developer. But if you replenish you'll never use up more that starter.

Photo Engineer · Sep 18, 2007

You don't need the starter. I never use it.

PE

Discpad · Sep 18, 2007

PE:

Isn't the RA RT for "roller transport," not room temperature?"

ben-s · Sep 18, 2007

Thanks PE, I suspected as much.
Do you trim the dev times when you use new solution?

Photo Engineer · Sep 18, 2007

I have no idea what RA-RT stands for, except that it is NOT 'room temperature'.

I use one set development time, and in drums my developer is one shot due to the pre-wet. In trays, I can get about 10 8x10 prints / liter at RT with 2' development time. The paper goes to completion, and so there is not much slop in result. As it exhausts, you see contrast and dmax going down. There is a color shift, but I forget which direction. I judge by eye and just slop some more developer into the tray to keep myself going in a big printing session. This method has kept me going all night printing.

PE

ben-s · Sep 18, 2007

Photo Engineer said:
...I judge by eye and just slop some more developer into the tray to keep myself going in a big printing session. This method has kept me going all night printing.

PE

Scientific and accurately measured then

How long do you prewet for? Is it the same 5 mins as used for film, or shorter?

Michel Hardy-Vallée · Sep 18, 2007

One thing I know is that the 1-Gallon sets of RA developer do not require starter. They contain parts A, B, C which you just mix together.

Photo Engineer · Sep 18, 2007

ben-s said:
Scientific and accurately measured then

How long do you prewet for? Is it the same 5 mins as used for film, or shorter?

I use a 1 minute prewet on the Jobo drum processor, but for tray processing I don't.

I measure to the square nanometer and to the 0.001 cc in volume. NAH, just dump and stir in some extra as you go along. After you have done it as long as I have, you develop a 'feel'. Its like swimming or riding a bike. Once you learn, you just don't forget!

The kit I use is the RA-RT developer replenisher. It is not the 1 gallon kit.

PE

ben-s · Sep 18, 2007

Photo Engineer said:
I use a 1 minute prewet on the Jobo drum processor, but for tray processing I don't.

I measure to the square nanometer and to the 0.001 cc in volume. NAH, just dump and stir in some extra as you go along. After you have done it as long as I have, you develop a 'feel'. Its like swimming or riding a bike. Once you learn, you just don't forget!

The kit I use is the RA-RT developer replenisher. It is not the 1 gallon kit.

PE

Hmmm... I prefer the angstrom and yoctolitre personally. So much more accurate

Thanks for your help!

Akki14 · Sep 18, 2007

So... let me get this straight... you can use the 35C/100F RA4 chemicals at "room temperature" 68F? It just takes longer with a yellow colour shift? Hmm...

Photo Engineer · Sep 18, 2007

That is correct.

I used about +10 to +20 Y correction and 2' development at 68F.

PE

Craig · Sep 18, 2007

Do you do the bleach and fix for 2' at 68F as well?

Photo Engineer · Sep 18, 2007

For paper, I use the Kodak RA blix for 2' and then wash for 5' at 85 deg F. If at 68 deg F, I wash for about 10 - 20 mins. This gives optimum washing for image stability.

Please see my other postings on this on APUG and PN for more details and a reversal cross process.

PE

Colour printing help?

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